1. Field of the Invention
The present invention relates generally to a storage apparatus and a start-up control method for the storage apparatus. Particularly, the invention relates to a technique of controlling electric power consumed by the storage apparatus.
2. Description of Related Art
A storage apparatus has: a plurality of disk devices that are managed by a RAID (Redundant Array of Inexpensive Disks) system and arranged in an array; and a controller for controlling the plurality of disk devices. The storage apparatus is connected to a host computer such as a server (hereinafter referred to as a “host”) and provides redundant logical storage areas (hereinafter also referred to as “logical volumes”) according to the RAID configuration.
Recently, the amount of data to be managed by, for example, business enterprises has been increasing day by day. Accordingly, the size of storage apparatuses is increasing and power consumption is also increasing. Also, the quantity of electronic devices including storage apparatuses installed at a data center or similar tends to increase, resulting in an increase in power consumption over the entire data center. The term “electronic devices” herein means equipment operated by power feeding.
Among various electronic devices installed at a data center or similar, there are electronic devices that can be switched from a normal operation mode to a power-saving mode, and electronic devices that perform operation control of their power-distributed portions so that power consumption can be reduced compared to the normal operation state by, for example, stopping power feeding.
U.S. Patent Application Publication No. 2005-0210304 discloses an example of a technique for limiting the power consumption of a storage apparatus contained in an electronic device. U.S. Patent Application Publication No. 2005-0210304 discloses a technique whereby when starting disk devices, a storage apparatus predicts power consumption after starting the disk devices, judges whether the predicted power consumption will exceed a predetermined threshold value, and controls starting or stopping of the disk devices based on the above judgment. According to U.S. Patent Application Publication No. 2005-0210304, power consumption of a storage apparatus can be reduced by limiting the power consumption of the storage apparatus to a predetermined threshold value or less by controlling starting or stopping of disk devices.
Japanese Patent Application Laid-Open (Kokai) Publication No. 2007-25733 discloses a technique whereby when an electronic device starts a power-saving mode, even if a control means for the electronic device is reset due to a power supply voltage drop, the power mode can be normally shifted to the power-saving mode by setting a power-saving flag to hold memory and starting the activation of the power-saving mode if the power saving flag in the hold memory is set after the electronic device is reset and then reactivated.
However, the conventional art does not give consideration to starting or restarting a storage apparatus when it is initially installed or added.
Specifically speaking, when the storage apparatus is divided into disk device or chassis units as power-saving control portions by using, for example, a MAID (Massive Arrays of Inactive Disks) technique and each power-saving control portion is to be started, it is necessary to be aware of the power consumption of the power-saving control portions to be started in order to keep the required power for each power-saving control portion at a predetermined power threshold value or less.
However, when initially installing or adding a storage apparatus, information about a new chassis, particularly its power consumption, is unknown. Therefore, if the power-saving control portion is started while the power consumption of the new chassis is unknown, it is difficult to keep the power consumption of the power-saving control portion at the threshold value or less.
Also, when restarting the storage apparatus, which power-saving control portion should be started cannot be ascertained without knowing the power consumption of each power-saving control portion. Therefore, if the power-saving control portion(s) are restarted while the power consumption of each power-saving controller portion is unknown, it is difficult to keep the power consumption of the power-saving control portion(s) at or under the threshold value.